Skip to main content

SpringWorks Therapeutics Announces Positive Topline Results from the Phase 2b ReNeu Trial of Mirdametinib in NF1-PN

Excellent news for both children & adults with plexiform neurofibromas! SpringWorks Therapeutics has released positive topline data from its Phase 2b clinical trial evaluating Mirdametinib, an investigational MEK inhibitor. Congratulations to the SpringWorks team, and thank you for being terrific partners to the NF and Children’s Tumor Foundation communities. As readers of this space may recall, CTF played a key role in encouraging Pfizer to ‘reposition’ mirdametinib so that it could be an asset for NF. We’re encouraged and excited by the next steps for the mirdametinib journey, and what it potentially means for NF patients.

Springworks’ press release is excerpted here: 

– Confirmed objective response rate of 52% in pediatric patients and 41% in adult patients, as assessed by Blinded Independent Central Review –

– Mirdametinib treatment resulted in deep and durable responses and significant improvements in key secondary patient-reported outcome measures –

– Mirdametinib was generally well tolerated with low rates of Grade 3+ adverse events –

– Additional data expected to be presented at medical conference and NDA submission to the U.S. FDA planned in the first half of 2024 –

– Company to host conference call today at 8:30 a.m. Eastern Time –

SpringWorks Therapeutics, Inc. (Nasdaq: SWTX), a clinical-stage biopharmaceutical company focused on developing life-changing medicines for patients with severe rare diseases and cancer, today announced positive topline results from the pivotal Phase 2b ReNeu trial evaluating mirdametinib, an investigational MEK inhibitor, in pediatric and adult patients with neurofibromatosis type 1-associated plexiform neurofibromas (NF1-PN).

The ReNeu trial enrolled 114 patients in two cohorts (pediatric and adult) across 50 sites in the U.S. The primary endpoint was confirmed objective response rate (ORR), defined as ≥ 20% reduction in target tumor volume as measured by MRI and assessed by Blinded Independent Central Review (BICR). As of the data cutoff date of September 20, 2023, 52% (29/56) of pediatric patients and 41% (24/58) of adult patients had BICR confirmed objective responses within the 24-cycle treatment period (cycle length: 28 days). An additional pediatric patient and two additional adult patients achieved confirmed objective responses after Cycle 24 in the long-term follow up phase of the trial, where patients continue to receive mirdametinib treatment. Median best percent change from baseline in target tumor volume was -42% and -41% in the pediatric and adult cohort, respectively. As of the data cut-off, the median duration of treatment was 22 months in both the pediatric and adult cohorts. Median duration of response was not reached in either cohort. Pediatric and adult patients in the ReNeu trial also experienced statistically significant improvements from baseline in pain, quality of life, and physical function, as assessed across multiple patient-reported outcome tools.

Read the SpringWorks press release here.

Read more about the Children's Tumor Foundation's partnership with SpringWorks here

Read more about repositioning drugs for rare disease treatment here